This invention relates to crushers usable in the crushing of materials such as rock, ore and the like, to produce crushed material of substantially reduced particle size. The invention has particular utility, and will be described herein, in the context of a crusher usable in the crushing of granite or basalt to produce gravel and fine material for the paving of roads and other surfaces. It is not intended by this description, however, to be limited to such a particular use of the apparatus.
Various types of crushers are known in the industry. Describing generally more common types of crushers, such include what might be referred to as a cone crusher, which includes a cone, usually rotated in an eccentric path, and working against an opposing support surface, to produce granulation. So-called roll crushers feature opposed rolls which are rotated to cause material to pass between the nip of the rolls producing a crushing action. So-called jaw crushers typically include opposed jaws with inclined crushing surfaces that pivot toward and away from each other, many times with an eccentric type of movement, to produce a crushing action.
A problem which has characterized many known types of crushers is an inability to handle efficiently a wide range of rock sizes. Further explaining, if the rock to be pulverized is in pieces of too large a size, many of the more common crushers will not accept such material, meaning that such must be preliminarily processed to reduce the material to such a size as to be accepted by the crusher. This is disadvantageous, of course, since it requires, in effect, multiple crushers, resulting in an increased capital outlay and introducing material handling problems. In other crushers, there is a problem of having the material work efficiently through the crusher during the crushing operation. For instance, in many jaw-type crushers, the construction is such that the crusher tends to work material upwardly against the flow of incoming material, impeding the flow of material through the crusher. With larger crushers, this is a more severe problem, because of the divergence required in the jaws at their upper extremities if the jaws are to receive product of large size. Crushers which utilize an oscillatory motion, where the crushing surfaces slide across each other, tend to be prone to wear problems by reason of the abrasive action produced by the rock under such a sliding action.
A general object of this invention is to provide an improved crusher which avoids or minimizes many of the above indicated problems characterizing prior art devices.
A more specific object is to provide an improved crusher which is capable of handling a wide range of material sizes.
Another object is to provide a crusher which includes a pair of opposed jaw members mounted for relative reciprocal movement toward and away from each other with such occurring in a substantially linear path.
Another object is to provide such a crusher where the jaw members have opposed, stepped, crushing face means, with plural opposed step portions of increasingly closer spacing progressing downwardly between the jaw members.
In a related object, a crusher is provide wherein each step portion is fronted by a crushing expanse extending substantially normal to the path of movement of a jaw member.
Another object is to provide such a crusher where the step portions in a jaw member are fronted by substantially vertical crushing expanses, and each such expanse is formed by the front surfaces of laterally spaced bars forming a grid in the crusher.
Another object is to provide a crusher wherein a jaw member is mounted on pivoted upstanding arms, which pivot at points spaced vertically from the path of movement of the jaw member, to provide in the jaw member a substantially lineal movement.